On Mon, May 26, 2003 at 03:46:37PM +1000, Anthony Towns wrote:
> Yes, that's true. There are two responses to this: one is that the
> benefits are worth the risks; the other is that (hopefully) the incentives
> to vote honestly
which are ... ?
> The only time voting against an option that only requires a simple
> majority is useful is if you can arrange for "A beats B, D beats A,
> B beats D" to be the outcome, thus getting A dropped, and B winning.
> However, to manage this, at least some proportion of the majority that
> thinks "A beats B" voters has to prefer making no decision to *either*,
? As far as I can see, all you need is enough D voters that B
voters can cause D beats A.
> at least we're acting on the votes we actually receive.
I believe that's true of most voting systems. :-)
> The question is whether, in particular (realistic) circumstances, some
> given strategy is more likely to produce a favourable outcome than
> voting sincerely.
... and also more likely than if a plain Condorcet method were used.
Which complicates the analysis, because it's easy to construct cases
where B voters can beat A with strategy under both Condorcet+SSD and
"approval+Condorcet+SSD". Here is a situation in which they are
different:
sincere strategy by BAD
9 ABD 9 ABD
6 BAD 6 BDA
3 DAB 3 DAB
2 DBA 2 DBA
Condorcet+SSD A A
approval+ A B
(Maybe this is the sort of situation you were referring to above?)
This does not answer the question, but I think it's a fairly strong
data point.
Andrew